A child rescued from Boko Haram in Sambisa forest carries a baby in front of a clinic at the Malkohi camp for Internally Displaced People. Reuters

Six Christian siblings - between the ages of three and fifteen - kidnapped by Boko Haram in Cameroon have safely escaped the clutches of the Islamic extremist group.

According to World Watch Monitor, the siblings were kidnapped from Moskota in the Far North region of Cameroon during a night raid carried out by Boko Haram in August. The Islamic militants killed the children's father, Adamu Nguda, and left their mother behind in a state of "total shock."

Nguda was a church elder in Mouldougwa before the family became displaced and moved to Moskota, WWM reports.

The children had been taken to Nigeria, where they were entrusted to the care of a woman. Miraculously, they managed to escape when the woman fell asleep early one evening. They reportedly traveled through the night and were able to find a track that led them to an area close to their home. At dawn, they reached Mayo, a small dried-up stream on the border, where they were found by members of the military.

The six children were taken to military headquarters in Mora for investigations and then went on to a health center for a medical check-up. It is not known if the children have been reunited with their mother yet.

The six children kidnapped from Moskota are among thousands of people abducted by Boko Haram over the years. In April 2014, the group, which pledged allegiance to ISIS in 2015, kidnapped 276 schoolgirls from Chibok in northern Nigeria, the region where the insurgency emerged several years ago.

Since 2014, when Cameroon went to war against Boko Haram, the jihadi group has killed at least 2,000 civilians and soldiers and abducted hundreds in the far north of the country, according to the International Crisis Group (ICG).

Since its emergence eight years ago, Boko Haram, whose name roughly translates to "Western education is forbidden," has killed at least 20,000 people in Nigeria, Cameroon, Niger and Chad and displaced more than 2.3 million people.

UNICEF reports that the number of children, mainly girls, used by Boko Haram as "human bombs" has quadrupled this year.

On Tuesday, five children were killed and two others wounded by a suicide bomber described as a "young girl" in a northern region of Cameroon.

"A suicide bomber blew herself up (on Tuesday) at around 19.45" in the village of Zamga, 2km from the Nigerian border, said a security officer responsible for the zone, reached from the capital Yaounde.

"Five children were killed and two others wounded," he said on condition of anonymity, adding that the suicide bomber was also killed in the blast.

The attack and the death toll were confirmed to AFP by another security source.